Water-craft



Nov. 26, 1963 '1, w. EcRoYD ETAL WATER-CRAFT f Filed June 25, 1962 VENTORS .JMJ J/s/frrmu acyl 235215K L osfE Mana; #NJ/S United States Patent O WATER-CRAFT .lohn Wightman Ecroytl, 1 Aldermary Road, Charlton, Manchester, England, and Derek .lohn Lodge, Hazel House, Carleton, Pontefract, England Filed June 25, 1962, Ser. No. 204,951 Claims priority, application Great Britain June 27, 1961 4 Claims. (C1. 114-665) This invention is concerned with water craft and is applicable to a wide variety of craft including ferries, rescue boats, and boats of larger and smaller types, including also high speed boats, hydro-planes, seaplanes, the floats of seaplanes and similar vessels, and to other forms of waterborne transport. A11 these water-borne items are referred to generically as boats in the following description.

In the normal boat, for example yacht, dinghy, speedboat or the like, almost the whole of the lateral displacement of water, as the boat moves forward, takes place across the front of the boat and there is therefore a very substantial thrust directly resisting the forward movement of the boat. Also the shape of the boat hull has always been such that the resistance offered by the water as the boat is urged forward resolves into a very large component directly opposing the forward movement and only a relatively small lateral component. This concentrated rearward thrust tends to limit the speed at which the boat may be propelled under a given power input Iand also dictates the necessity of having a certain type and weight of frame structure in the boat in order to distribute the concentrated stresses involved. All this common practice, although of very long standing in boat construction, is believed by the applicants to be based on imperfect, misconceived principles.

It is an object of the present invention therefore, to overcome the said traditional diiculties and limitations, and so to shape a boat hull that the resistant thrust against forward movement is much reduced, and is distributed progressively along the length of the boat instead of being concentrated Aat the front, this advantage being obtained irrespective of the angle of the boat to the horizontal, which angle is largely dependent on the speed of the boat. In attempts to smooth out the sailing of boats attention has been concentrated mainly on modifying the upwardly pointed front end. The present applicant has found that success does not lie lhere for in fact, with his invention the boat may, in many cases be cut square across the front.

It is a further object of the invention so to shape the submersible part of the boat that the boat is not adversely affected by the shock of on-coming waves. In boats as hitherto known, the impact of a wave on the prow of the boat involves the whole weight of the wave, and that impact is transmitted as a shock to all parts, of the boat. The present invention seeks to avoid this by allowing large parts of the wave to escape obstruction by the boat instead of there being complete obstruction by the boat 4as hitherto.

According to this invention the boat is formed at its submersible part with one, two, or more longitudinallydirected formations having `downwardly-converging sides (for example substantially of V-section) and so located that when the boat is in the horizontal position (c g. when drifting) these formations are submerged -along their Whole length, to a depth governed by the weight of the boat and its load (if any) but, as the front of the boat becomes elevated as speed is acquired, the water line runs from a point in the bottom of each formation lat a greater or less distance from the front, this distance depending on the elevation, to a point in the top of each such formation at the back. Accordingly, each such formation acts las a forwardly-moving wedge (in plan) and takes the opposing thrust distributively along the whole of the 3,111,924 Patented Nov. 26, 1963 ICC submerged part, and to an increasing extent from front to back. The length of such wedge varies according to the depth of immersion and to the angle of elevation assumed by the boat. In consequence of this wedging action, the opposing force of the water is resolved into longitudinal and lateral components which have a different ratio at different points along the length of the submerged parts, with much less disparity between them at any such point than obtains in the normal boat. The said longitudinal formations may, land usually will extend beyond the front of the boat and may also extend beyond the rear of the boat.

it is an advantage arising from the use lof this invention that the prow of the boat may be much more square across than in the normal boat hulls, thereby increasing the carrying capacity and the ease of movement in the front end of the boat.

According to another feature of the invention, the said longitudinal formations `are made hollow from end to end so that a large proportion of the water beating against the prow of the boat will travel through said -hollow formations and thereby much reduce the wave shock. By this means, the crests of waves meeting the prow of the boat are cut off and allowed to pass through said hollow formations, the boat riding on the bases of the waves.

According toa further `feature of the invention the said longitudinal formations have the downwardly-converging side walls extending as longitudinal flanges along the lower edge, providing in each formation kan inverted longitudinal channel between them in which lair may become entrapped as the boat moves forward at speed. In such conditions the front of such channels is out of the water, and the `air which becomes located between said anges and above the water reduces the frictional resistance of the water against the forward movement of the boat.

In the more usual forms of the invention, there will be two yof said V-shaped longitudinal formations, identical in shape and size, and lying parallel to each other one at each side of the central plane of the boat. They may be arranged so that their outer wall constitutes a chine of the hull.

In the accompanying drawing a representative example of boat incorporating the invention is illustrated. -It is to be understood however that the invention may be applied also to other types tof boat, large and small, and whether propelled lby Ioutboard or inboard means. In the drawings:

FlG. 1 is a perspective view of the boat from the stern end;

FIG. 2 is a similar perspective view from the bow;

FIG. 3 is a front end view;

FIG. 4 is a diagram-matic section showing one way of fabricating the longitudinal V-sectioned parts and also illustrating a modification; and

FIGS. 5, 6 and 7 are 'diagrams illustrating the attitude of the lboat to the water in different conditions of loading `and surface.

As shown, the boat has a hull 1 which is cu-t square across at the front 2 and at the rear 3, the fairing 4 extending forwardly of the Ihull and being provided with a mooring edge 5. The boat is propelled by an outboard motor 6 and is steered from a Iwheel 7. Seats for the occupants are not shown. The cutting of the boat front square aero-ss is not an essential feature of the invention as, in some cases the hull may taper forwardly. It is however desirable that there ishould be no front fonrnation tending to give an upward lift to the hull.

The boa-t has a flat bottom 8, below which are attached two mutually-parallel substantially V-sectioned planes 9. These planes are open t-o the front and rear. Each plane has a length less than twelve times its height, and covers more than `one half the area of the bottom of the boat. They have downwardly-converging sides, -a horizontal -bottom 9a and internal i'langes 9b at the top by which they can be secured t the underside of the hull, by means of suitable bolts. In FIG. 4 there is shown a mode of constructing the planes by securing together separately-formed side and bottom parts. Many other modes of construction are of course available. FIG. 4 also illustrates how the side walls may extend below the bottom 9a to form Aa shallow inverted channel. In this channel, when the plane is elevated, air becomes trapped and tends to reduce the friction between the plane and the water.

In a modification, not illustrated, the sides of the planes 9 could be curved, either convex outwardly or concave outwardly, they could be rounded at the bottom instead of being at, or could meet at a peak. They may also be of increasing or decreasing cross-sectional size from end to end. There may be more than two such planes or, in a suitable case there could be one only, the bottom part 9a in that event being made much wider.

It may `be understood from a consideration of FIGS. 5-7 that there is no direct rearward thrust against the front of the boat when it is moving forwards yunder power. As soon as the boat begins to move forwards under power it assumes an upwardly tilted attitude, the angle of tilt increasing as the speed increases and, in that attitude the rearward thrust of the water is against the side faces of the planes 9 and is distributed over so much of the length of the plane as is still immersed. This results in great freedom from shocks and very much minimises any tendency for the boat to rise or pitch. Moreover, in the zone between the water and the bottom of the boat, and between the planes an air pocket or cushion is formed, exerting an upward pressure on the tilted boat to an extent determined by the speed of the boat.

In an experimental boat 10' length built substantially as the one illustrated it was found that the hull rises clear of the Water at so low a speed as 5 miles per hour. In broken water the planes 9 cut through the waves, as illustrated in FIG. 5,'cutting olf the wave crests 10', and ride smoothly on the base of the waves. The wave crests pass through the hollow planes easily without affecting the speed of `displacement of the boat. The said experimental boat achieved a speed of 40 miles per hour with a 40 horse power motor and at all speeds was proved to be safe, easily manoeuvrable, and had the minimum `of vertical movement or yloss of speed when driven through the wash of another boat.

In water too rough for the boat to operate at high speeds, the immersed parts of the planes 9 were found to be useful in resisting land damping sideways and vertical movement without interfering to any noticeable eX- tent with forward movement of the boat.

FIG. 6 illustrates lthe normal riding of the boat at speed, and FIG. 7 illustrates the riding of the boat when heavily laden, i

Various constructional Amodifications may be made within the scope of the above definitions.

The invention may be put into practice, alternatively by the attachment of planes 9 to the normal hull of a boat. In this case the planes would be straight along their lower edges as `in the embodiment illustrated, but along their upper edges they would be profiled to mate with the -outer surface of the boat hull.

What we claim is:

1. A boat comprising a hull which includes a fiat generally horizontally extending bottom, two hollow channel members extending longitudinally of said hull and adjacent said bottom, said channel members secured in spaced relationship to opposite sides of said bottom, each channel member being longer than said bottom and projecting beyond opposite ends thereof, portions of said channel members projecting beyond opposite sides of said bottom to increase the stability of said boat, said channel members each comprising a pair of rectangular flat plates having straight bottom edges parallel to `said bottom and rigidly secured together, said plates diverging in an upward direction so as to form a V-shaped channel therebetween and between said bottom, said V-shaped channel having open ends, and the upper edge of each of said tlat plates lixedly secured directly to said bottom whereby each of said channel members strengthens said bottom `and makes it more rigid, said bottom edges of said pair of plates being spaced laterally and secured together by a flat bottom plate parallel to said bottom, and said bottom plate being spaced a slight distance above the bottom edges of said pair of plates so as to provide a passage for trapping air.

2. A boat as defined in claim l, wherein said plates are composed of sheet metal, the upper edge portions of said plates being bent back upon themselves to form flanges of triangular cross section, said iianges rigidly secured directly to said bottom.

3. A boat `as defined in claim 2, wherein the ends of said channel members are canted so as to converge in an upward direction.

4. A boat `as defined in claim 3, wherein each channel member has a -length less than twelve times its height, and said channel members cover more than one half the area of said bottom.

References Cited in the file of this patent UNITED STATES PATENTS 2,794,192 Palris June 4, 1957 2,821,948 Harkson Feb. 4, 1958 2,855,885 Thomas Oct. 14, 1958 3,013,515 Morel Dec. 19, 1961 FOREIGN PATENTS 42,431 Switzerland Dec. 1l, 1907 492,450 Great Britain Sept. 21, 1938 544,239 Great Britain Apr. 2, 1942 819,482 France July 12, 19,37 

1. A BOAT COMPRISING A HULL WHICH INCLUDES A FLAT GENERALLY HORIZONTALLY EXTENDING BOTTOM, TWO HOLLOW CHANNEL MEMBERS EXTENDING LONGITUDINALLY OF SAID HULL AND ADJACENT SAID BOTTOM, SAID CHANNEL MEMBERS SECURED IN SPACED RELATIONSHIP TO OPPOSITE SIDES OF SAID BOTTOM, EACH CHANNEL MEMBER BEING LONGER THAN SAID BOTTOM AND PROJECTING BEYOND OPPOSITE ENDS THEREOF, PORTIONS OF SAID CHANNEL MEMBERS PROJECTING BEYOND OPPOSITE SIDES OF SAID BOTTOM TO INCREASE THE STABILITY OF SAID BOAT, SAID CHANNEL MEMBERS EACH COMPRISING A PAIR OF RECTANGULAR FLAT PLATES HAVING STRAIGHT BOTTOM EDGES PARALLEL TO SAID BOTTOM AND RIGIDLY SECURED TOGETHER, SAID PLATES DIVERGING IN AN UPWARD DIRECTION SO AS TO FORM A V-SHAPED CHANNEL THEREBETWEEN AND BETWEEN SAID BOTTOM, SAID V-SHAPED CHANNEL HAVING OPEN ENDS, AND THE UPPER EDGE OF EACH OF SAID FLAT PLATES FIXEDLY SECURED DIRECTLY TO SAID BOTTOM WHEREBY EACH OF SAID CHANNEL MEMBERS STRENGTHENS SAID BOTTOM AND MAKES IT MORE RIGID, SAID BOTTOM EDGES OF SAID PAIR OF PLATES BEING SPACED LATERALLY AND SECURED TOGETHER BY A FLAT BOTTOM PLATE PARALLEL TO SAID BOTTOM, AND SAID BOTTOM PLATE BEING SPACED A SLIGHT DISTANCE ABOVE THE BOTTOM EDGES OF SAID PAIR OF PLATES SO AS TO PROVIDE A PASSAGE FOR TRAPPING AIR. 